Ornamental sweetpotato plant named ‘Sweet Caroline Green’

ABSTRACT

A new and distinct ornamental cultivar of Ipomoea batatas called &#39;Sweet Caroline Green&#39; is described that is a compact plant, with a round mounded shape, a dense canopy and dark green leaves that are deeply lobed. The plant is further distinguished by its unusual leaves, which have 3-5 narrow lobes, with prominent light green palmate veins. In addition, this cultivar has a reduced vigor as compared with existing cultivars of Ipomoea batatas known to the inventors. Ipomoea batatas &#39;Sweet Caroline Green&#39; is suitable for use in landscaping and containerized gardens.

Latin name of the genus and species: The Latin name of the novel,ornamental plant variety disclosed herein is Ipomoea batatas (L.) Lam.

Variety denomination: The inventive cultivar of Ipomoea batatasdisclosed herein has been given the variety denomination ‘Sweet CarolineGreen’.

BACKGROUND OF THE INVENTION

Ipomoea species are members of the morning glory family Convolvulaceae.Ipomoea batatas, commonly referred to as the white or yellow sweetpotatoand the orange yam, are typically fast growing vines withpalmately-lobed leaves. These ornamental species produce storage rootsidentical in appearance to the common sweet potato, but not aspalatable. Late in the growing season, tubular flowers appear which aresimilar to morning glories, but plantings are dominated by theappearance of the foliage. The plants are highly desirable due to theirability to grow under varied stress conditions, cover a large space, andlast the entire growing season. Moreover, these plants have few insector disease problems.

Existing varieties of Ipomoea batatas are popular for landscapingapplications. There are currently six common types of ornamentalsweetpotatoes that are being cultivated primarily for annual, summervines. These six cultivars are: ‘Blackie’ (unpatented), having darkpurple-black foliage, lavender flowers, and edible storage roots;‘Terrace Lime’ (unpatented) and ‘Margarita’ (unpatented; also known as‘Sulfur’), which have large brilliant chartreuse leaves and lavenderblooms; ‘Black Heart’ (unpatented; also known as ‘Ace of Spades’),having heart-shaped leaves with burgundy purple color; ‘Tricolor’(unpatented; also known as ‘Pink Frost’), is a variegated plant whichhas pale green, white, and pink-margined leaves; and ‘Lady Fingers’,(unpatented), which has medium green, dainty leaves divided into long,thin, fingerlike lobes which are complemented by burgundy stems andveins.

Ipomoea batatas ‘Margarita’ has recently been released in the UnitedStates, and has become widely used as a landscape annual. It is notsuitable for mixed containers, as it exhibits a very vigorous growth andtends to out-compete other species. Another popular variety is‘Blackie’, a vigorous purple-leaved clone which is also unsuited tocontainerized gardens. See Armitage. A. M. and J. M. Garner. 2001.Ipomoea batatas ‘Margarita’. HortScience 36:178.

Therefore, to meet the current horticultural demand, it is desirable toproduce new, more robust cultivars of ornamental sweetpotato withattractive foliage colors, leaf shapes, and plant architectures. Inaddition, it would be advantageous to develop cultivars of ornamentalsweetpotato exhibiting a more compact growth, and which do notout-compete other species in mixed containers.

The present invention comprises a new and distinct variety of Ipomoeabatatas, which has been named ‘Sweet Caroline Green’. The variety issuitable for use as a landscape or containerized plant.

Lineage. The Ipomoea batatas ‘Sweet Caroline Green’ cultivar originatedfrom a conventional cross between Ipomoea batatas cultivarsNC93-15XBL-1ORN (the female parent; not patented) and NCSXBR7-52ORN (themale parent; not patented) conducted in the Winter of 1998-1999 at theHorticultural Greenhouses located at North Carolina State University,Raleigh, N.C. NC93-15XBL-1ORN was a cross between an orange fleshedbreeding line NC93-15 and ‘Blackie’. NCSXBR7-52ORN was a cross between‘Sulfur’ and ‘Blackie’. Seeds from this cross were planted in theHorticultural Greenhouses in May 1999 and in a field at North CarolinaState University in July 1999. The single, individual plant now known asIpomoea batatas ‘Sweet Caroline Green’ was selected in October 1999because of its combination of exceptional features, and has beenpropagated asexually since that time.

Asexual Reproduction. Since its selection, Ipomoea batatas ‘SweetCaroline Green’ has been asexually reproduced at the HorticulturalGreenhouses located at North Carolina State University, Raleigh, N.C.predominantly by vegetative propagation of vine cuttings. Asexualpropagation of the new cultivar by cuttings at the location previouslystated has shown that the unique features of this new OrnamentalSweetpotato are stable and the plant reproduces true to type insuccessive generations of asexual propagation.

SUMMARY OF THE INVENTION

The present Ipomoea batatas ‘Sweet Caroline Green’ ornamental plant is acompact rounded cultivar, having a dense canopy, with dark green leavesthat are very deeply lobed. The unusual leaves have 3-5 narrow lobeswith prominent light green palmate veins. Furthermore, this plant has areduced vigor and growth rate as compared with other cultivars ofIpomoea batatas known to the inventors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a color photograph of a typical plant of the Ipomoea batatas‘Sweet Caroline Green’ grown in a container under commercial greenhouseconditions.

FIG. 2 shows the variety of leaves produced by Ipomoea batatas ‘SweetCaroline Green’ and the lower surface of the leaf (upper left leaf).

FIG. 3 shows a top view of a typical plant of the Ipomoea batatas ‘SweetCaroline Green’ grown in a container under commercial greenhouseconditions.

FIG. 4 shows the flesh and skin of a storage root.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of the botanical characteristicsof a new and distinct cultivar of Ipomoea batatas plant known by thecultivar name Ipomoea batatas ‘Sweet Caroline Green’. All colors citedherein refer to The Royal Horticultural Society Colour Chart (The RoyalHorticultural Society, London, 1995 edition) designations except wheregeneral terms of ordinary dictionary significance are used. Wheredimensions, sizes, colors, and other characteristics are given, it is tobe understood that such characteristics are approximations or averagesset forth as accurately as practicable.

The descriptions reported herein are from 12-week-old specimens grownindividually in six-inch azalea pots. The plants were grown in Lompoc,Calif., under commercial practice in a polycarbonate-covered greenhouseduring the 2001-2002 winter season with day and night temperaturesranging between 18.3-26.7° C. and 15.6-18.3° C., respectively, and lightlevels of about 4,000-8,000 foot-candles. Ipomoea batatas ‘SweetCaroline Green’ has not been observed under all possible environmentalconditions; therefore, the phenotype may vary with variations in theenvironment such as season, temperature, light intensity, day length,cultural conditions, and the like.

Growth Conditions. Ipomoea batatas ‘Sweet Caroline Green’ has goodvigor, a moderate growth rate, and is very adaptable to containerculture. In locales with mild winter conditions, Ipomoea batatas ‘SweetCaroline Green’ will grow perennially; otherwise it is an annual plantthat is killed by frost. In the greenhouse setting described above,after twelve weeks of growth, plants of this cultivar produce compact,round-mounded, herbaceous plants averaging 15 cm in height and 28 cm inlength. Similar to cultivated sweetpotatoes, wind or rain rarely causesmuch damage to ‘Sweet Caroline Green’, but if damage does occur, theplant drops the damaged leaves and grows new shoots at nodes where theleaves were lost. Under low light levels in a greenhouse, ‘SweetCaroline Green’ can develop intumescence, which will remain on theaffected foliage, but will be outgrown with new foliage.

Above-Ground Structure and Coloration. FIGS. 1 and 3 show the shape andcoloration of typical plants of Ipomoea batatas ‘Sweet Caroline Green’.Overall, this cultivar is a compact, mound shaped, andoutwardly-spreading, herbaceous plant with a dense canopy and an averageheight of 15 cm and an average area of spread of 22×28 cm.

Branching Habitat. Freely-branching with approximately two basalbranches and ˜12 lateral branches per basal branch. Dense growth with nopinching required to stimulate branching.

Stem (Color: 144A). Round and smooth with an outward aspect and verygood strength. Stem tends to undulate or zigzag between the alternatenodes. Length: ˜10.0 cm, Diameter: ˜0.4 cm. Internodes are stacked withan average length of ˜0.8-1.0 cm.

Vegetative Lateral Branches (Color 144A). Same as stems for mostcharacteristics. Length: ˜10.0 cm. Diameter: ˜0.4 cm. Internodes arestacked with an average length of ˜0.8-1.0 cm.

Petiole (Color: 144B). Mature Petiole Length: ˜6.5 cm with broadvariation (see FIG. 2). Diameter: ˜0.2 cm.

Foliage. Leaves are alternate and simple. Further, the leaves arepalmate and are deeply divided into 3-5 lobes with sinuses nearly to themid-vein. Quantity: Densely foliated, with ˜10-12 leaves per lateralbranch. Leaf shape is very consistent, but varies in size (see FIG. 2).Mature leaf length: ˜6.0 cm. Mature leaf width: ˜7.0 cm. Leaf margin isentire, but deeply divided. Lobe length: ˜4.0 cm. Lobe width: ˜0.8 cm.Mid-vein lobe width: ˜1.7 cm. Leaf apex: Acute. Leaf base: Acute. Leafhas a smooth texture and matte finish. Venation is palmate at base witharcuate veins in the center lamina. Color: see Table 1.

TABLE 1 Leaf Structure Upper Surface Lower Surface Young Leaf 138A 147BMature Leaf 147A 147B Vein 147B 147C

Flowers. Cultivar ‘Sweet Caroline Green’ does flower sporadicallythroughout the season in response to a variety of stressful conditions(e.g., drought, nutrient stress, cloudy weather). Flowering is enhancedby shorter day lengths; however the precise photoperiod for flowerinduction is not known. The inflorescence is generally a cyme in whichthe peduncle is divided into two axillary peduncles. Each peduncle isfurther divided into two after the flower is produced. Usually buds ofthe first, second and third order are developed, but sometimes singleflowers are produced. The corolla is composed of five fused petals thatform a funnel with a round limb. Corolla width: ˜3.5 cm, corolla length:˜3.6 cm. The corolla is not fragrant. The limb and outer throat arelavender and the inner throat purple. Inner limb color: 78D, Outer limbcolor: 78D, Inner throat color: 78A, Outer throat color: 78D. There arefive sepals, which are elliptic with an acute apex and green in color.Each flower has one pistil, with a cream colored style. The stigma iscream colored and has two segments. The stigma is exerted relative tothe stamens. The ovary is yellow and superior with two locules thatcontain one or two ovules. At the base of the ovary there are basalglands containing nectar. There are five cream colored anthers. Pollenis scarce. True seed are not easy to obtain because the plant does notflower readily and the seed set averages less than 15% true seed. Thereis some variation in flower size and color, depending on theenvironmental conditions. Descriptions are based on: CIP, AVRDC, IBPGR.1991. Descriptors for Sweet Potato. Huaman, Z., editor. InternationalBoard for Plant Genetic Resources, Rome, Italy.

Storage Roots. As shown in FIG. 4, the storage roots have a light orangeskin (Color 165C) with predominantly light orange flesh (Color 159A)mottled with orange (Color 170C) and purple (Color 70B) flecks and anarrow (˜2 mm) orange (Color 159A) ring notable under the epidermis.Shapes are highly irregular and vary considerably in length and diameterdepending on growing conditions. A minimum of 150 days are needed toproduce storage roots that meet the size criteria for United StatesDepartment of Agriculture (USDA) U.S. No. 1 grade (5.1-8.9 cm indiameter and 7.6 to 22.9 cm in length), but very few of these storageroots would meet the shape criteria for U.S. No. 1 grade. Underconditions in which the plant grows perennially, the storage roots willcontinue to grow as long as the roots are healthy and the weatherremains warm.

Comparison With Other Ipomoea batatas Cultivars. Of the six most commoncultivars of ornamental sweetpotato, Ipomoea batatas ‘Sweet CarolineGreen’ most resembles the ‘Lady Fingers’ cultivar. Both cultivars aregreen and have deeply lobed leaves, but Ipomoea batatas ‘Sweet CarolineGreen’ has green veins on the lower surface (see FIG. 2) and ‘LadyFingers’ has purplish-red veins on the lower surface. Moreover, ‘LadyFingers’ is the most vigorous of the ornamental Ipomoea batatascultivars on the market, whereas ‘Sweet Caroline Green’ has a reducedvigor which makes it suitable for cultivation in a mixed container withother species. Furthermore, ‘Sweet Caroline Green’ has a compact, densemound of foliage reaching a plant height of ˜15 cm and ‘Lady Fingers’has a trailing plant habit reaching a plant height of ˜20 cm.

‘Sweet Caroline Green’ is quite distinct in its features as comparedwith its female parent, as shown in Table 2.

TABLE 2 Female Parent Leaf Structure ‘Sweet Caroline Green’NC93-15XBL-1ORN Plant Habit Compact Trailing Foliage Color Green PurpleLeaf Shape Very Deeply Very Deeply Lobed Leaves Lobed Leaves

The male parent was used for crossing and has since been discarded. Thisvariety had purplish-green foliage, but no other data were collectedfrom this clone.

Disease or Pest Resistance. ‘Sweet Caroline Green’ is susceptible toSweetpotato Feathery Mottle Virus and damage by Japanese beetles.

Herbarium voucher. A voucher of ‘Sweet Caroline Green’ will be depositedinto the Herbarium of North Carolina State University (NCSU) in Raleigh,N.C. upon patenting.

What is claimed is:
 1. A new and distinct cultivar of Ipomoea batatasplant named ‘Sweet Caroline Green’, substantially as illustrated anddescribed herein.